Conventional modern detergent compositions for washing fabrics are complex mixtures of ingredients which act to remove soil from the fabric during the washing process. Such compositions comprise one or more surface active agents or surfactants which act to lower the surface tension of the washing solution, thus enabling the dissolution or dispersion of soil into the washing solution. The oldest example of such a surfactant is soap which was already used by the ancient Egyptians.
A significant improvement in the cleaning performance of detergent compositions was obtained by the addition of so-called builders, which enhance the cleaning action of the composition by complexing calcium ions which are present in hard water. Examples of such builders are sodium tripolyphosphate (STP), nitrilotriacetate (NTA) and zeolite.
A further significant improvement in the performance of detergent compositions was achieved by the addition of bleaching systems which react chemically with stains present on the fabrics and thereby decolorize the stains. Examples of efficient bleaching systems are tetra acetyl ethylene diamine (TAED)/sodium perborate, and sodium nonanoyloxybenzene sulphonate (SNOBS).
Another significant improvement in the performance of detergent compositions was achieved by the addition of enzymes to detergent compositions. The use of protease in fabric washing compositions is most wide spread, whereas lipases, amylases and cellulases are used less frequently.
Although each of the above improvements has been successful to a certain extent, there is still a need to provide alternative or further improved detergent compositions. In particular, there is a need for effective cleaning action against specific coloured stains which are often difficult to remove. It is therefor an object of the present invention to provide effective alternative or improved detergent compositions for fabric washing. It is a further object of the present invention to provide an effective alternative or improved process for washing fabrics.
We have now surprisingly found that these and other objects can be achieved by the detergent compositions of the invention, which are characterized in that they comprise one or more surfactants and a compound which is capable of binding to a coloured substance which may occur as stains on fabrics.